JPS63286305A - Rubber vulcanizing can - Google Patents

Abstract

PURPOSE:To enable volcanization in a short period of time by making heat conduction efficiency favorable, by a method wherein a tubular body constituting a heating flow path of steam poured into a can through outside of the can and discharged outside of the can in a separated state from a heating medium within the can is provided within a can body and an external circumferential surface of the can body is made into a heating surface for unvulcanized rubber. CONSTITUTION:An external circumferential surface of a metallic tubular body 3 mounted on a truck 4 for vulcanization running on rails within a can body 1 constitutes a heating surface for unvulcanized rubber UR to be set up on an external circumferential surface as a sheating. Then opening parts 5, 6 on both ends of the metallic tubular body 3 are connected respectively with flexible tubes 7, 8. The one side flexible tube 7 is connected with an introducing hole 9 for steam on an upper wall of a vulcanizing can 1 which can be connected with an outside steam supply source. Therefore, the external surface of the unvulcanized rubber is heated and vulcanized indirectly with a heating medium within the can. Moreover, the external surface of the unvulcanized rubber is indirectly heated and vulcanized and it is also heated and vulcanized from inside not only through steam supplied from the outside steam supply source but also through the metallic tubular body 3, which is under a closed state.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to rubber vulcanization cans, particularly rubber linings that cover the inner or outer surfaces of metal bodies with rubber vulcanizate, and metal tube bodies (mandrels). This invention relates to the improvement of rubber vulcanizing cans for mandrel-type rubber hoses, etc., which are formed by molding on top and removing the metal tube body after vulcanization.

[Conventional technology]

Conventionally, for this type of vulcanization, a so-called direct vulcanization can, in which high-pressure heated steam is directly sealed inside the vulcanization can, has often been used.

[Problem that the invention seeks to solve]

However, since this direct vulcanization can encapsulates pressurized and heated steam, it is necessary to maintain sufficient pressure resistance, and the pressure resistance strength σ (kMccm2) is determined by the plate thickness k (cm2).
), the internal pressure P (kg/Cm2) and the pipe inner diameter r (cm
) is inversely proportional to - When the house pressure P increases by 1, if the pressure strength σ is kept constant, the larger the vulcanized can, the larger the plate thickness k, which becomes difficult to manufacture. The drawback is that the price also increases. In addition, when steam comes into direct contact with the rubber surface, some of the compositions in the rubber compound may react or be extracted with the steam, resulting in changes in the physical properties of the rubber. When vulcanizing cloth-tight rubber moldings, there was a problem in that the cloth deteriorated considerably due to steam. Also, direct vulcanization cans are corroded by high-temperature steam, so they have the disadvantage that they must be designed with corrosion allowances taken into consideration in advance.

On the other hand, in order to obtain the temperature necessary for vulcanization, in a direct vulcanizing can, the pressure of steam sealed inside the can must be increased in proportion to the temperature. There is an indirect vulcanizer that uses air or other inert gas as a medium and obtains the vulcanization temperature by heating the air or inert gas. This indirect vulcanization method can achieve high temperatures without steam pressurization like in direct vulcanization, and
Since the steam does not come into direct contact with the rubber surface, the composition in the rubber compound reacts with the steam and is extracted.
This is an extremely preferable method because it does not cause any change in the physical properties of the rubber and there is no problem with the deterioration of the tightening material.On the other hand, since the heating medium is air or an inert gas, direct steam is applied. Compared to direct vulcanization cans, the disadvantage is that the efficiency of heating the rubber is extremely poor. Therefore, especially when obtaining a thick rubber product, an indirect vulcanization can requires several times as much curing time as a direct vulcanization can, which poses a problem in processability and workability.

Therefore, the purpose of this invention is to focus on the high efficiency of heat conduction in a direct vulcanization can and the high temperature under low pressure in an indirect vulcanization can, and to make it possible to obtain high temperature even at low pressure, and to achieve high heat conduction efficiency. It is a rubber vulcanizer that improves vulcanization and enables vulcanization in a short time, and also achieves the advantages of an indirect vulcanizer, such as reducing the extraction and reaction of the rubber compound composition and preventing the deterioration of the tightening fabric. There is a place that provides sulfur cans.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has been proposed to provide a so-called indirect method in which heating pipes are installed to heat the heat medium in the can, such as air, and indirectly heat the unvulcanized rubber. While the basic structure is a vulcanizing can, we have adopted a special technical means of installing a metal tube with a certain configuration inside the vulcanizing can. A tube that forms a heating flow path for steam that is injected from outside the can and discharged outside the can while isolated from the heating medium, and its outer peripheral surface serves as a heating surface for the unvulcanized rubber that is set on the outer peripheral surface. It is configured.

[Effect]

Since the present invention is as described above, even when heated, water vapor does not come into direct contact with the unvulcanized rubber, so the rubber compound composition is less likely to be denatured, and deterioration of the tightening fabric is prevented as much as possible. Moreover, in addition to the indirect vulcanization method, the unvulcanized rubber set on the outer circumferential surface of the metal tube is directly heated from the inside by the steam passing through the metal tube, so the heat transfer efficiency is remarkable. Since the vulcanization process is good, vulcanization can be done much more quickly than conventional indirect vulcanization cans.

〔Example〕

An embodiment of the present invention shown in the accompanying drawings will be described in detail below.

In FIG. 1, reference numeral 1 denotes a horizontal cylindrical vulcanizing can, with an opening/closing lid 2 attached to the side. In this vulcanizing can 1, a heating tube (not shown) is housed in the lower part of the can over almost its entire length. It uses an indirect heating configuration.

On the other hand, 3 is a tube body made of metal or the like installed horizontally inside the vulcanizing can 1 on a vulcanizing cart 4 running on a rail, and the entire body is sealed except for openings 5 and 6 at both ends. The outer circumferential surface constitutes the heating surface of the unvulcanized rubber UR' which is set on the outer circumferential surface. Further, flexible tubes 7.8 are connected to the openings 5.6 at both ends of the tube body 3 made of metal, etc., and one flexible tube 7 is connected to the steam introduction hole 9 in the upper wall of the vulcanizing can 1. , which can be connected to an external steam source. The other flexible duplex 8 is connected to a connecting pipe 10 extending in the direction of the opening/closing lid 2, which is disposed below the pipe body 3 made of metal or the like, and the other end opening of the connecting pipe 10 has a A flexible tube 12 is connected to a steam discharge hole 11 in the lower wall of the vulcanizing can 1 .

Therefore, like a normal indirect vulcanization can, the outer surface of the unvulcanized rubber is indirectly heated and vulcanized by the heat medium inside the can, and also from the steam supplied from an external steam source.
The tube body 3, which is made of metal or the like, is kept in a sealed state, and is heated and vulcanized from the inner side as well.

However, the present invention is not limited to any of the configurations of the above embodiments. For example, the tube body 3 may be made of materials other than metal, and may also be made of heat-resistant plastic material. Further, the supply of steam to the inner space of the metal pipe body 3 is not limited to any particular embodiment. Further, the vulcanization can may also be formed in a vertical manner. In short, if the configuration basically adopts the configuration of an indirect vulcanization can, but at the same time installs a tube body made of metal or the like that heats the unvulcanized rubber by conductive heat in a non-contact state in the vulcanization can 1, All can be adopted.

Next, using the rubber vulcanization can according to the above example, a certain test was conducted using a rubber hose as an object to be vulcanized. For comparison, conventional direct and indirect rubber vulcanization cans were also tested.

The design conditions of each vulcanizing can and the conditions of the rubber to be vulcanized are as shown below.

@Table 1 [Note] *Each dimension symbol is as shown in Figure 2. Temperature measurement is performed on the inner surface of the rubber (■), the center of the rubber (■), and the surface of the rubber (■).
■) Measurements were taken at each point.

*The rubber surface was constructed by wrapping a nylon tightening cloth twice.

*The rubber compound R is as follows.

Table 2, Figure 3 shows the vulcanization time (minutes) and the temperature (°C) at each measurement point.
).

As is clear from FIG. 3, in this example, vulcanization heating was generally faster than in the comparative example, and the vulcanization was particularly remarkable on the inner surface of the rubber (■), and the vulcanization on the rubber center (■) and the rubber surface was more rapid. Vulcanization in (■) is observed to proceed in a state similar to that of .

Next, the physical properties of the rubber R obtained by this vulcanization were examined and were as follows. In particular, since the most important part of a rubber hose is the rubber on its inner surface, the physical properties were measured at a position close to the inner surface. Table 3 shows the results after 60 minutes of vulcanization, and Table 4 shows the results after 90 minutes of vulcanization. For comparison, the amount of press vulcanization at 143°C is also shown.

Table 3 Table 4 〔note〕 All measurements were taken using JIS K6301.

As a result, it was confirmed that the rubber vulcanized with the vulcanizing can of the example had better physical properties than those of other vulcanizing cans, and had good properties at the same vulcanization time. is recognized. Moreover, especially in the case of a rubber hose, since the physical properties of the rubber inner surface are good, a suitable rubber hose can be provided.

Table 5 shows a comparison of various properties other than the above-mentioned physical properties.

Table 5 below (note) *Vulcanization time and amount of steam used These are the time and amount of steam used when the vulcanization state progresses to an equilibrium saturated state.

*Deterioration of fastening Indicates the number of times the nylon fabric can be used repeatedly.

As the above results show, when the vulcanizing can according to this example is used, the vulcanization time is reduced to 115 to 1/2 compared to the conventional indirect vulcanizing can, and the vulcanizing time is reduced to 1/2 compared to the conventional indirect vulcanizing can. Steam consumption is reduced by 10-20% compared to sulfur cans. In addition, the can body cost is significantly reduced compared to direct vulcanization cans (the plate thickness is 1/2), and the temperature inside the can is well distributed or dispersed, and there is no local heating, resulting in high temperatures. Vulcanization becomes possible.

In addition, there is less corrosion inside the can than in a directly vulcanized can, and there is little deterioration of the cloth even if it is a molded product using tightening rubber.

In addition to little change in rubber properties, it is advantageous in that it can be cooled efficiently in a short period of time, and is safe because it uses low pressure.

〔Effect of the invention〕

As described above, the rubber vulcanizing can according to the present invention can achieve a dramatic improvement in vulcanization heating speed, which was not possible with conventional indirect vulcanizing cans, and also achieve Rubber vulcanization has made it possible to achieve high temperatures under low pressure and to impart good properties to the rubber after vulcanization, which was not possible with sulfur cans, and it has contributed greatly to this technical field. We were able to provide cans.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an embodiment of the rubber vulcanizing can according to the present invention, Figure 2 is a schematic diagram showing the design conditions for testing the same vulcanizing can, and Figure 3 is the test results. FIG. 2 is a diagram showing the relationship between rubber vulcanization time and temperature at each point.

Claims (1)

[Claims] (1) In a rubber vulcanizing can that is equipped with a heating tube that heats an internal heating medium such as air and indirectly heats unvulcanized rubber, the inside of the rubber vulcanizing can is connected to the internal heating medium. A pipe made of metal or the like is installed to form a heating flow path for water vapor that is injected from outside the can and discharged outside the can in an isolated state, and the outer circumferential surface of the pipe made of metal or the like is sheathed on this outer circumferential surface. A rubber vulcanizing can characterized by having a heating surface made of sulfurized rubber.